import java.util.*;
class Example2_5 {
   public static void main(String args[]) {
     int start = 0,end,middle;
     int a[] = {12,45,67,89,123,-45,67,20165330};
     int N = a.length;
     for(int i=0;i<N;i++) {   //选择发排序数组
     for(int j=i+1;j<N;j++) {
         if(a[j] < a[i]) {
           int t = a[j];
           a[j] = a[i];
           a[i] = t;
          }
        }
      }
     Scanner scanner = new Scanner(System.in);
     System.out.println("输入整数，程序判断该整数是否在数组中:");
     int number = scanner.nextInt();
     int count = 0;
     end = N;
     middle=(start+end)/2;
     while(number!=a[middle]){
         if(number>a[middle])
            start = middle;
         
         else if(number<a[middle])
           end = middle;
         middle = (start+end)/2;
         count++;
         if(count>N/2)
           break;
     }
     if(count>N/2)
       System.out.printf("%d不在数组中.\n",number);
     else
       System.out.printf("%d在数组中.\n",number);
  
}
}
